The present invention relates to a mounting unit for fastening an injection member for dosing a fluid into an exhaust system of an internal combustion engine on an exhaust tract, and to an exhaust-gas aftertreatment arrangement having a mounting unit of said type.
It is known to install a particle filter in an exhaust system of an internal combustion engine of a vehicle. If the internal combustion engine is a diesel engine, the particle filter acts for example as a soot filter and, owing to its filtering action, reduces the emissions of fine dust. To prevent the filter becoming blocked after a certain operating duration, it is necessary for the filter to be regenerated from time to time. The regeneration takes place by means of a temperature increase to for example approximately 600 degrees Celsius, as a result of which the particles, in particular soot particles, are burned. Since this is not possible by engine-internal measures in all operating situations, the temperature increase is realized by means of fuel, for example diesel, which is injected into the drivetrain via an injection member. The injected fuel passes to an oxidation catalytic converter arranged upstream of the particle filter. The fuel which passes into the oxidation catalytic converter is oxidized or burned and leads to an increase in the exhaust-gas temperature, such that correspondingly hot gases pass to the downstream particle filter and, there, effect the regeneration.
In another method, a urea solution is injected into the exhaust tract for the selective catalytic reduction of nitrogen oxides in exhaust gases in an SCR catalytic converter.
There is therefore a need for a device which makes it possible to inject liquid into an exhaust tract.
A device for introducing a liquid substance into the exhaust gas of an internal combustion engine is described in DE 10 2007 003 120 A1. DE 10 2006 049 531 A1 describes a connecting unit having a port for a dosing module for mounting in an exhaust tract of an internal combustion engine.
During operation, the exhaust line is heated to a high temperature by the hot exhaust gases of the internal combustion engine. The high temperature of the exhaust line is transferred to the injection member. A high temperature at the injection member causes aging of the liquid to be injected, and can thus adversely affect the action of said liquid.